[Neoplastic angioendotheliosis: a case of T cell lymphoma positive for S-100 protein].

A 63-year-old woman presented with painless, firm, subcutaneous nodules on her legs and trunk. The lesions were annular or serpiginous and their surface was livid-red to pale-red. Superficial lymph nodes were not palpable. Upper gastrointestinal series, barium enema, Ga scintigraphy, and CT findings were negative. Histological examination revealed deep dermal vessels occupied by neoplastic cells and fibrin thrombi. We diagnosed her as having neoplastic angioendotheliosis. Electron microscopically, tumor cells lacked Weibel-Palade bodies. Immunohistochemically, the tumor cells were positive for leukocyte common antigen, T11, MT-1, HLA-DR and S-100 protein. They were negative for Factor VIII-related antigen, epithelial membrane antigen, carcinoembryonic antigen, B-1, and B-2. Immunoelectron microscopic study showed that their nuclei, cytoplasma, and cell membranes were positive for S-100 protein. Based on these findings, we diagnosed her as having T cell lymphoma. The patient rejected chemotherapy and was discharged. Three months after discharge, right hemiplegia developed. Brain CT scan revealed enhanced masses in the left frontal, temporal, and occipital lobes. Craniotomy showed only gliosis and hemorrhage. She died of cerebral bleeding three months after craniotomy.